Evaluation of Yield Stability and Drought Tolerance of Barley Genotypes in Temperate Regions of the Iran

Drought stress is one of the results of climate change that has a negative impact on the growth and yield of crops. Breeding for drought tolerance and production stability are important goals of crop breeding programs in arid and semi-arid regions.

In order to evaluate the stability of grain yield and drought tolerance at barley genotypes in temperate climates of Iran, 20 cultivars and barley lines, in a randomized complete block design with three replications during the two cropping years 2016-2017 and 2017-97 in four stations including Karaj, Varamin, Birjand and Yazd were evaluated under two conditions, normal irrigation and drought stress at the end of the season (irrigation interruption in 50% of heading).

Combined analysis of variance showed that the effects of genotype, year × location, location × genotype and genotype × year × location on grain yield was significant. In order to study the interactions of genotype × environment more precisely and to determine genotypes with stable and drought tolerant yield, different stability parameters and drought tolerance and susceptibility indices were calculated for each genotype. Calculation of stability parameters showed that lines 20, 4, 16 and 15 were recognized as genotypes with stable yield and suitable adaptation, respectively. In terms of drought tolerance indices in the first year, lines 4, 17, 16, 20 and 11 and in the second year, lines 7, 3, 16, 4, 20 and 5, the top genotypes were drought tolerant at the end of the season.

The use of drought tolerance and susceptibility indices, three-dimensional charts and biplot in the first and second years showed that lines 4, 16 and 20 were jointly selected as the best genotypes in terms of drought tolerance in both years, so this the results showed that these lines had good repeatability for drought tolerance. On the other hand, stability statistics also indicated the stability of yield of these lines. so due to grain yield stability, drought tolerance and high yield potential, three lines 4, 16 and 20 were superior and adaptable  lines for normal and terminal drought stress conditions in the temperate climate of Iran that after supplementary  tests can be considered to help production in these areas.